Adaptive Detection of a Moving Target Undergoing Illumination Changes against a Dynamic Background

Mu Lu,Yang Gao,Ming Zhu 한국광학회 2016 Current Optics and Photonics Vol.20 No.6

A detection algorithm, based on the combined local-global (CLG) optical-flow model and Gaussianpyramid for a moving target appearing against a dynamic background, can compensate for the inadaptabilityof the classic Horn–Schunck algorithm to illumination changes and reduce the number of neededcalculations. Incorporating the hypothesis of gradient conservation into the traditional CLG optical-flowmodel and combining structure and texture decomposition enable this algorithm to minimize the impactof illumination changes on optical-flow estimates. Further, calculating optical-flow with the Gaussianpyramid by layers and computing optical-flow at other points using an optical-flow iterative with highergray-level points together reduce the number of calculations required to improve detection efficiency. Finally, this proposed method achieves the detection of a moving target against a dynamic background,according to the background motion vector determined by the displacement and magnitude of theoptical-flow. Simulation results indicate that this algorithm, in comparison to the traditional Horn-Schunckoptical-flow algorithm, accurately detects a moving target undergoing illumination changes against adynamic background and simultaneously demonstrates a significant reduction in the number of computationsneeded to improve detection efficiency.

Community Knowledge and Support of Ecotourism in the World Heritages Sites of Simien Mountain National Park

Tewodros Abuhay(Tewodros Abuhay ),Endalkachew Teshome(Endalkachew Teshome ),Gashaw Mulu(Gashaw Mulu ) People&Global Business Association 2023 Global Business and Finance Review Vol.28 No.4

Purpose: An in-depth investigation into locals' familiarity with and support for ecotourism development is necessary to ensure the long-term viability of responsible and sustainable tourism. This study aimed to assess the protected area communities' knowledge and level of support for eco-tourism and its development in the Semien Mountain National Park, North Gondar, Ethiopia. Design/methodology/approach: The study employed a mixed research approach and an explanatory design. A multi- stage sampling was used to select 397 samples of respondents from three districts. As methods for gathering data, surveys, interviews and focus group discussions were all employed. Percentages, averages, t-tests, analysis of variance, regression models and thematic analysis were used to analyze the data. Findings: More than half of the respondents (57.2%) were unable to know what tourist is, even though the study found that 93.5% of respondents had a fair understanding of what tourism involved. Nearly three-quarters of the respondents said that their main sources of tourism-related information were their friends and the government. In the multiple regression model, all independent variables together account for about 38.7% of the total variance in the dependent variable. Only three factors significantly contributed to the prediction of the variation in ecotourism support: ecotourism benefit (β = 24, p = 0.001, gender (β =0.47, p = 0.000), and family size (β=0.12, p =.005. Research limitations/implications: Variables, time, and space were limitations on this study. All elements influencing local communities' support for ecotourism development were not exhaustively considered. This research may not apply to other places with differing social, cultural, and environmental settings. This study is also cross-sectional, which means it does not provide information on how local understanding and support for ecotourism may evolve over time. Originality/value: Many studies have examined the consequences of tourism on host communities and tourist attitudes toward ecotourism, but few have examined local understanding and support of ecotourism development. As a result, this study can provide novel perspectives and knowledge that can enhance comprehension of this phenomenon, influence policymaking and practical applications, and ultimately foster the progression of the field.

Effects of load variation on a Kaplan turbine runner

Amiri, K.,Mulu, B.,Cervantes, M.J.,Raisee, M. Korean Society for Fluid machinery 2016 International journal of fluid machinery and syste Vol.9 No.2

Introduction of intermittent electricity production systems like wind and solar power to electricity market together with the deregulation of electricity markets resulted in numerous start/stops, load variations and off-design operation of water turbines. Hydraulic turbines suffer from the varying loads exerted on their stationary and rotating parts during load variations since they are not designed for such operating conditions. Investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of a rotating vortex rope (RVR) in the draft tube. The RVR induces pressure pulsations in the axial and rotating directions called plunging and rotating modes, respectively. This results in oscillating forces with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. This study investigates the effect of transient operations on the pressure fluctuations exerted on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors for this purpose. The model was run in off-cam mode during different load variations. The results showed that the transients between the best efficiency point and the high load occurs in a smooth way. However, during transitions to the part load a RVR forms in the draft tube which induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode. Formation of the RVR during the load rejections coincides with sudden pressure change on the runner while its mitigation occurs in a smooth way.

Effects of load variation on a Kaplan turbine runner

K. Amiri,B. Mulu,M.J. Cervantes,M. Raisee 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.2

Introduction of intermittent electricity production systems like wind and solar power to electricity market together with the deregulation of electricity markets resulted in numerous start/stops, load variations and off-design operation of water turbines. Hydraulic turbines suffer from the varying loads exerted on their stationary and rotating parts during load variations since they are not designed for such operating conditions. Investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of a rotating vortex rope (RVR) in the draft tube. The RVR induces pressure pulsations in the axial and rotating directions called plunging and rotating modes, respectively. This results in oscillating forces with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. This study investigates the effect of transient operations on the pressure fluctuations exerted on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors for this purpose. The model was run in off-cam mode during different load variations. The results showed that the transients between the best efficiency point and the high load occurs in a smooth way. However, during transitions to the part load a RVR forms in the draft tube which induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode. Formation of the RVR during the load rejections coincides with sudden pressure change on the runner while its mitigation occurs in a smooth way.

Occupational exposure to sharps injury among healthcare providers in Ethiopia regional hospitals

Nigussie Tadesse Sharew,Getaneh Baye Mulu,Tesfa Dejenie Habtewold,Kefyalew Dagne Gizachew 대한직업환경의학회 2017 대한직업환경의학회지 Vol.29 No.-

Background: Sharps injury is a penetrating stab wound from a needle, scalpel, or another sharp object that may result in exposure to blood or other body fluids. According to World Health Organization pooled estimate, the annual incidence of sharps injury in Africa was ranged from 2.10 to 4.68 per person per year, but research data in Ethiopia is limited. The aim of the study was to investigate sharps injury prevalence and associated risk factors. Methods: Institution based cross-sectional study was conducted with 200 healthcare providers (HCP) in Northeast Ethiopia. Proportionate stratified sampling was used to select HCP. Sharps injury during the last 12 months was an outcome variable whereas demographic characteristics, behavioral attributes, and job environment characteristics were independent variables. Data was collected from April to May 2016 using self-administered questionnaire; which was adapted from World Health Organization best practices for injections and related procedures toolkit. Bivariate and multivariate logistic regression analysis was carried out to identify sharps injury associated risk factors. Epi Info version 3.5.1 software package was used for data coding and entry whereas Statistical Package for Social Sciences (SPSS) version 20 software package was used for analysis. Results: In total, 195 HCP participated with a response rate of 97.5%. The prevalence of sharps injury was 32.8%. Following adjustment for covariates, lack of in-service job training and previous exposure to sharps injury were statistically significant risk factors for sharps injury. HCP who had no in-service job training were 4.7 times more likely sustained sharps injury compared with those who had in-service job training (p < 0.001, OR = 4.7, 95% CI = 2.05–10.56). HCP who had previous exposure to sharps injury were 3.7 times more likely sustained sharps injury compared with those who were not exposed (p-value = 0.002, OR = 3.7, 95% CI = 1.62–8.27). Conclusions: This study revealed 32.8% or at least three out of ten HCP exposed to sharps injury. This was found statistically significant among HCP who had no in-service job training and who had previous exposure to sharps injury. Thus, training HCP perhaps increase their skill and curiosity to reduce exposure to sharps injury.